1. Field of the Invention
The present invention relates to an alignment guide device attached to a towing dolly for use by drivers of large, multi trailer/trailer/van rigs, also variously referred to as eighteen wheelers and tractor-trailer rigs, and, more particularly, to a device for assisting drivers of such multi trailer/trailer/van rigs to align a dolly in preparation for engagement with a rearmost trailer/trailer/van.
2. General Background of the Invention
Interstate trucking now commonly involves the use of multiple trailer/van rigs. In some states the use of multiple trailers is limited to Interstate or Toll roads, and the relative size of the vans may be limited. The second trailer or van is coupled to the rear of the first with a towing dolly which includes a fifth wheel device similar to that contained on the rear of the tow vehicle or tractor. Though these multiple unit rigs have been in common and expanding use over many years, the coupling of the vehicle elements at the outset of the trip remains a daunting exercise. The approach to the coupling starts with the coupling of the tractor to the first trailer. This is a straight forward exercise, with the trailer and fifth wheel in (relatively) full view. Once the first trailer is attached, it is then necessary to attach the towing dolly and the second trailer. One must either first, independently hitch a towing dolly to the second trailer and then back the first trailer into coupled relation with the towing dolly, or vice versa: back the first trailer into coupled relation with the towing dolly and then back the towing dolly (which is behind the first trailer) into coupled relation with the second trailer (aligning the fifth wheel on the towing dolly and hitching with the king/connecting pin on the second trailer). The first action requires considerable time and frequently the interaction of a separate tractor to move or position the towing dolly. Towing dollys are heavy, cumbersome and not easily moved without a tractor. The second action is extremely time consuming without the use of an alignment assist or guide of some sort (including a spotter to signal the driver) locking the towing dolly into a relative alignment position with the first trailer, with respect to the maneuvering activity by the driver/tractor in backing the towing dolly under the second trailer.
Big rig drivers, irrespective of experience and skill level, find it challenging to efficiently connect multiple trailer/vans to their tractor. Where there is but one trailer/van, e.g., a standard 53 foot trailer/van, or trailer, hooked up to a tractor, it is relatively simple to back the tractor under the fifth wheel king pin, lock it in place by means of the jaws on the lower fifth wheel hitch, connect the air hoses and electrical lines and drive away.
The style of trailer/van towing has evolved over the years to exhibit an increasing number of rigs comprising a tractor with two trailer/vans connected in tandem. Smaller trailer/vans are more flexible and, by pulling two such trailer/vans with a single tractor, it is more efficient to drop each trailer/van in a different locale, rather than unloading a portion of the larger trailer/van in one locale and taking the remainder of the load to another location.
With the advent of multiple trailer/van rigs, the trucking industry became more flexible and versatile, but the driver had the added task of hooking up the second, or rearward trailer/van. He did so, and does today, by means of an arduous multi step process which may take as much as thirty to forty minutes.
For example, the driver will first use the tractor to align a towing dolly with the rear trailer/van. He then hooks up the tractor to the forward trailer/van and backs up the forward trailer/van to the towing dolly which he has previously positioned. He then couples the towing dolly to the rear of the forward trailer/van, typically by a pintle hitch, and thereafter backs the towing dolly, which has been previously aligned, into the proper connective position, under the fifth wheel king pin of a second, or rear, trailer/van.
While easy to describe, the effort is not without its problems. The difficulty in such a multi tasking maneuver arises from several factors. Keeping in mind that during the backing operation, the forward trailer/van is free to move laterally (e.g., turn right or left) around the king pin engaged in the lower fifth wheel hitch and move up and down with variations in the terrain. Likewise, it should also be appreciated that the towing dolly is free to move about the pintle hitch. As a consequence, any relatively slight left or right turn of the tractor while backing up is likely to be exaggerated at the towing dolly, making control and alignment of the last element (the towing dolly) all that much more difficult.
Thus, to guide the fifth wheel hitch of the towing dolly under the king pin of the rear trailer/van, the driver must keep both the forward trailer/van and the towing dolly in essentially coaxial alignment, which is not an easy task and often requires more than one attempt to achieve proper alignment. If one also considers changes in elevation or roughness in the surface of the road, heights and other dimensions of the respective trailer/vans, or less than perfect visibility, an already difficult maneuver is exacerbated.